[PATCH v2 1/2] PM / Domains: Add genpd_power_on/off trace events

[Matthias Kaehlcke]

The events can be useful for power analysis/optimization, e.g.
to track the state of power domains during suspend/resume on
battery powered devices.

Signed-off-by: Matthias Kaehlcke <mka@xxxxxxxxxxxx>
---

Changes in v2:
- split original patch in two, one for genpd_power_on/off and
  one for genpd_set_performance_state
- use trace_genpd_power_on/off_enabled macros to eliminate
  branches when the tracepoints are disabled
- updated commit message (original subject was "PM / Domains:
  Add tracepoints")

 drivers/base/power/domain.c  | 26 ++++++++++++++++++++++----
 include/trace/events/power.h | 31 +++++++++++++++++++++++++++++++
 2 files changed, 53 insertions(+), 4 deletions(-)

diff --git a/drivers/base/power/domain.c b/drivers/base/power/domain.c
index 584cf7a60f57..88eff9c4e79a 100644
--- a/drivers/base/power/domain.c
+++ b/drivers/base/power/domain.c
@@ -20,6 +20,7 @@
 #include <linux/sched.h>
 #include <linux/suspend.h>
 #include <linux/export.h>
+#include <trace/events/power.h>
 
 #include "power.h"
 
@@ -422,14 +423,22 @@ static int _genpd_power_on(struct generic_pm_domain *genpd, bool timed)
 	if (!genpd->power_on)
 		return 0;
 
-	if (!timed)
-		return genpd->power_on(genpd);
+	if (!timed) {
+		ret = genpd->power_on(genpd);
+
+		if (trace_genpd_power_on_enabled() && !ret)
+			trace_genpd_power_on(genpd);
+
+		return ret;
+	}
 
 	time_start = ktime_get();
 	ret = genpd->power_on(genpd);
 	if (ret)
 		return ret;
 
+	trace_genpd_power_on(genpd);
+
 	elapsed_ns = ktime_to_ns(ktime_sub(ktime_get(), time_start));
 	if (elapsed_ns <= genpd->states[state_idx].power_on_latency_ns)
 		return ret;
@@ -452,14 +461,23 @@ static int _genpd_power_off(struct generic_pm_domain *genpd, bool timed)
 	if (!genpd->power_off)
 		return 0;
 
-	if (!timed)
-		return genpd->power_off(genpd);
+	if (!timed) {
+		ret = genpd->power_off(genpd);
+
+		if (trace_genpd_power_off_enabled() && !ret)
+			trace_genpd_power_off(genpd);
+
+		return ret;
+	}
 
 	time_start = ktime_get();
 	ret = genpd->power_off(genpd);
 	if (ret == -EBUSY)
 		return ret;
 
+	if (trace_genpd_power_off_enabled() && !ret)
+		trace_genpd_power_off(genpd);
+
 	elapsed_ns = ktime_to_ns(ktime_sub(ktime_get(), time_start));
 	if (elapsed_ns <= genpd->states[state_idx].power_off_latency_ns)
 		return ret;
diff --git a/include/trace/events/power.h b/include/trace/events/power.h
index f7aece721aed..d92cb53c20ed 100644
--- a/include/trace/events/power.h
+++ b/include/trace/events/power.h
@@ -7,6 +7,7 @@
 
 #include <linux/cpufreq.h>
 #include <linux/ktime.h>
+#include <linux/pm_domain.h>
 #include <linux/pm_qos.h>
 #include <linux/tracepoint.h>
 #include <linux/trace_events.h>
@@ -529,6 +530,36 @@ DEFINE_EVENT(dev_pm_qos_request, dev_pm_qos_remove_request,
 
 	TP_ARGS(name, type, new_value)
 );
+
+#ifdef CONFIG_PM_GENERIC_DOMAINS
+DECLARE_EVENT_CLASS(genpd_power_on_off,
+	TP_PROTO(struct generic_pm_domain *genpd),
+
+	TP_ARGS(genpd),
+
+	TP_STRUCT__entry(
+		__string(name, genpd->name)
+	),
+
+	TP_fast_assign(
+		__assign_str(name, genpd->name);
+	),
+
+	TP_printk("name=%s", __get_str(name))
+);
+
+DEFINE_EVENT(genpd_power_on_off, genpd_power_on,
+	TP_PROTO(struct generic_pm_domain *genpd),
+
+	TP_ARGS(genpd)
+);
+
+DEFINE_EVENT(genpd_power_on_off, genpd_power_off,
+	TP_PROTO(struct generic_pm_domain *genpd),
+
+	TP_ARGS(genpd)
+);
+#endif /* CONFIG_PM_GENERIC_DOMAINS */
 #endif /* _TRACE_POWER_H */
 
 /* This part must be outside protection */
-- 
2.23.0.444.g18eeb5a265-goog